Currently, thin film transistor liquid crystal displays (TFT-LCDs) have become a mainstream display product. A TFT-LCD primarily comprises a color filter substrate and an array substrate disposed opposing to each other, with liquid crystals filled in between the color filter substrate and the array substrate. In order to correctly orient the liquid crystal molecules, a layer of alignment solution is coated on the surfaces of the array substrate and the color filter substrate, respectively. A layer of alignment film forms on the array substrate and the color filter substrate from the alignment solution. Subsequently, the alignment films on the array substrate and the color filter substrate are rubbed with a rubbing cloth. By rubbing, microscopic grooves are formed on the surface of the alignment films so that the liquid crystal molecules are initially arranged regularly along the alignment of the grooves.
In a conventional process for the array substrate and the color filter substrate, the alignment solution is generally coated simultaneously on more than two substrates (array substrates or color filter substrates) in a same masterboard, and finally the masterboard is divided to yield single array substrates or color filter substrates.
The device for coating an alignment solution is, e.g., shown in FIG. 1. First, the alignment solution 101 is added dropwise via a dispenser 102 to the contacting position between an anilox roll 103 and a blade roll 104; the alignment solution 101 on the anilox roll 103, which is rotating, is spread uniformly by the blade roll 104; the anilox roll 103 is brought to contact with the transfer printing plate 105 having a preformed pattern, transferring the alignment solution onto the transfer printing plate 105; and finally, the alignment solution 101 is printed onto the surface of the masterboard 107 on the base 106 by the transfer printing plate 105 which is rotating, so as to form the alignment film 108. The diagrammatic schematic view of the lateral expansion of the existing transfer printing plate is shown in FIG. 2, and its planar diagrammatic schematic view is shown in FIG. 3. The transfer printing plate 105 comprises a basal membrane 109 and a transfer layer 110. There are more than two convex transfer regions 111 that correspond to substrates in the masterboard, respectively, and non-transfer regions 112 disposed between transfer regions 111 in the transfer layer 110.
For the aforementioned device for coating an alignment solution, because the individual transfer regions 111 correspond to the individual substrates in the masterboard 107, and the alignment solution 101 tends to accumulate in the peripheral region of the individual transfer regions 111, the alignment solution 101 accumulated in the peripheral region tend to be further transferred to the display region of the substrate, causing the uneven nature of the alignment film 108 on the substrate and resulting in an uneven or too thick peripheral region (halo) of the alignment film 108. This renders the liquid crystal molecules in the peripheral regions of the finally prepared products unable to be oriented normally, causing the shrinking of the display area of the substrate that can function normally. In addition, the aforementioned transfer printing plate 105 is prone to issues of deviational printing of the alignment film 108, further causing the shrinking of the display area of the substrate that can function normally.